1009 Product of Polynomials (Python实现)

港控/mmm° 2023-06-19 09:56 115阅读 0赞

This time, you are supposed to find A×B where A and B are two polynomials.

### Input Specification: ###

Each input file contains one test case. Each case occupies 2 lines, and each line contains the information of a polynomial:

K N1 aN1 N2 aN2 ... NK aNK

where K is the number of nonzero terms in the polynomial, Ni and aNi (i=1,2,⋯,K) are the exponents and coefficients, respectively. It is given that 1≤K≤10, 0≤NK<⋯<N2<N1≤1000.

### Output Specification: ###

For each test case you should output the product of A and B in one line, with the same format as the input. Notice that there must be **NO** extra space at the end of each line. Please be accurate up to 1 decimal place.

### Sample Input: ###

2 1 2.4 0 3.2
    2 2 1.5 1 0.5

### Sample Output: ###

3 3 3.6 2 6.0 1 1.6

### Python实现： ###

dic1 = {}
    dic2 = {}
    dic = {}
    x = input().split()
    for j in range(1, len(x)):
        if j % 2 == 1:
            dic1[int(x[j])] = float(x[j + 1])
    x = input().split()
    for j in range(1, len(x)):
        if j % 2 == 1:
            dic2[int(x[j])] = float(x[j + 1])
    dic1_keys = list(dic1.keys())
    dic2_keys = list(dic2.keys())
    for i in dic1_keys:
        for j in dic2_keys:
            try:
                dic[i+j] += dic1[i]*dic2[j]
            except KeyError:
                dic[i + j] = dic1[i] * dic2[j]
    sorted_dic = sorted(dic.items(), key=lambda z: z[0], reverse=True)
    list1 = []
    for i in range(len(dic)):
        if sorted_dic[i][1] != 0:
            list1.append(str(sorted_dic[i][0]))
            list1.append(str(round(sorted_dic[i][1], 1)))
    if len(list1) == 0:
        print("0")
    else:
        print(int(len(list1) / 2), end=" ")
        print(" ".join(list1))
    # 需要注意：
    # 1.系数为0的情况需要过滤
    # 2.结果为0时不能带空格